1. Field of the Invention
The present invention generally relates to rotary head drum apparatuses, and more particularly, to a rotary head drum apparatus having a rotary transformer.
2. Description of the Related Art
Generally, rotary head drum apparatuses are used in video tape recorders and digital audio tape recorders (hereinafter referred to as “DATs”) as means for performing a magnetic recording/reproducing process on magnetic tapes (recording media). A rotary head drum apparatus is formed by, for example, a lower fixed (stator) drum and an upper rotary drum. Four, for example, magnetic heads are mounted on the upper rotary drum at predetermined intervals. Thus, as the upper rotary drum is rotated, the magnetic heads are also rotated, and a magnetic recording/reproducing process is performed on a magnetic tape that is wound around the rotary head drum apparatus in a helical manner.
FIG. 1 shows a conventional rotary head drum apparatus 1. A rotary drum 2 is rotated on a stator drum 3 by rotating a shaft 5. The shaft 5 is press fit into a shaft opening 6 of the rotary drum 2 and rotated by a motor 4 provided under the stator drum 3.
A magnetic head 8 held by a head base 7 is provided to the rotary drum 2. The head base 7 is formed by, for example, a metal substrate, and the magnetic head 8 is provided at an end of the head base 7. The head base 7 is fixed to a bottom surface of the rotary drum 2 by a head fixing screw 9.
A rotating-side rotary transformer 10, which forms a rotary transformer, is fixed to the bottom of the rotary drum 2. The rotating-side rotary transformer 10 is positioned to face a stator-side rotary transformer 11 that is provided to the stator drum 3. A coil 12 is wound on each of the rotating-side rotary transformer 10 and the stator-side rotary transformer 11. The rotating-side rotary transformer 10 and the stator-side rotary transformer 11 send and receive signals without contacting each other between the rotary drum 2 and the stator drum 3 by an electromagnetic induction effect between the coils 12.
A terminal 13 is provided on the rotating-side rotary transformer 10. A terminal 14 electrically connected with the magnetic head 8 is provided on the terminal 13. An end of the coil 12 is electrically connected to the terminal 14. Thus, it is possible to supply a signal reproduced by the magnetic head 8 to a signal flexible substrate (not shown) that is provided to the stator drum 3 via the terminal 13, the rotating-side rotary transformer 10, and the stator-side rotary transformer 11. In addition, a recording signal from the signal flexible substrate may be supplied to the magnetic head 8 via the rotating-side rotary transformer 11, the stator-side rotary transformer 10, and the terminal 13.
The rotary drum 2 includes a cylindrical connecting part 2a disposed at a position facing the rotating-side rotary transformer 10. An adhesive providing part 15 is formed in an end surface of the cylindrical connecting part 2a. The adhesive providing part 15 is filled with an adhesive 16 for fixing the rotating-side rotary transformer 10 to the rotary drum 2. The rotating-side rotary transformer 10 is fixed to the rotary drum 2 with the adhesive 16. It should be noted that the height of the adhesive providing part 15 is about 0.2–0.3 mm at most.
Referring more closely to the terminal 13, which is provided on the top surface of the rotating-side rotary transformer 10, an end of the terminal 13 abuts the outside wall of the cylindrical connecting part 2a of the rotary drum 2, and a groove is formed in a bottom portion of the abutting portion of the terminal 13 to serve as an adhesive splashing prevention part 17.
The adhesive splashing prevention part 17 is provided in order to prevent excessive adhesive 16 from splashing from the adhesive providing part 15. Thus, even if the adhesive 16 splashes from the adhesive providing part 15, the adhesive splashing prevention part 17 provided in close vicinity of the adhesive providing part 15 prevents further splashing. Hence, it is possible to prevent peripheral devices of the rotary head drum apparatus 1 from being contaminated by the adhesive 16.
Experience shows that, since the rotary head drum apparatus 1 is produced in large quantities, there is a possibility that the adhesive 16 may be excessively applied in a filling process of the adhesive 16. Conventionally, an excessive adhesive is typically removed by a worker wiping away the excessive adhesive. However, by providing the adhesive splashing prevention part 17, it is possible to eliminate such a wiping operation (refer to Japanese Laid-Open Patent Application No. 2000-195025, pages 4–6, and FIGS. 1–3 for example).
However, the adhesive splashing prevention part 17 is formed by forming a groove in the terminal 13, which is a thin member. It is a difficult operation to form a groove in a thin member. In this case, there is a problem in that required time and costs are increased.
Additionally, the adhesive splashing prevention part 17 is formed by forming a relatively small groove at the end of the terminal 13, as it is too difficult to form a large groove in a thin member. Consequently, with such a thin member and such a small groove, in a case where a large amount of the adhesive 16 splashes from the adhesive providing part 15, it is difficult or impossible to receive all of the splashing adhesive 16 in the groove.